(b. 1507, China—d. 1566/67, China), reign name (nianhao) of the 11th emperor of the Ming dynasty (1368–1644), whose long reign (1521–66/67) added a degree of stability to the government but whose neglect of official duties ushered in an era of misrule.

Notoriously cruel, Jiajing caused hundreds of officials who had the temerity to disagree with him to be tortured, demoted, or killed. He spent much of his time and money, especially in his later years, patronizing Daoist alchemists in the hopes of finding an elixir to prolong his life. The government was left in the hands of a few favourites who allowed the situation on China's borders to deteriorate. Mongol tribesmen under the leadership of Altan Khan (died 1583) raided the northwest frontier and several times even besieged the Chinese capital at Beijing. Japanese pirates harassed trade along the coast, and rebellions in the southern provinces were frequent. Jiajing's successors, however, were able to revive Ming power temporarily.